Alcohol-related disorders impose a substantial burden on society with far-reaching health consequences. The identification of novel genes and genetic pathways that influence alcohol-related behaviors will facilitate the development of new therapeutic interventions for alcoholism and other forms of alcohol abuse. In this project we will investigate genes and genetic pathways that have novel influences on ethanol behavior. Molecular-genetic information from this project should ultimately lead to better diagnosis, risk determination and treatment of alcohol-related disorders in humans. This project focuses on Clic4/Clic as a novel mouse/Drosophila gene that affects behavioral responses to ethanol. Preliminary studies indicate that this gene influences ethanol-related behavior in both fruit flies (Drosophila) and mice, suggesting that it has a conserved role in ethanol action. To further characterize Clic4/Clic and its associated molecular mechanisms in ethanol behavior, we have developed a coordinated study in Drosophila and mice. Using the Drosophila model, this project will identify the tissue site of Clic action (Aim 1), define the temporal requirements for Clic (Ai 2) and delineate molecular-genetic mechanisms of Clic function (Aim 3). Using the mouse model, this project will further characterize ethanol regulation of Clic4 in the brain (Aim 4A), characterize the role of mammalian Clic4 in drinking and other ethanol behaviors (Aim 4B), characterize downstream molecular responses to altered Clic4 expression (Aim 4C), and investigate the role of a focused set of molecular partners implicated in Clic4 action (Aim 4D). This project draws on the complementary expertise of two independent laboratories directed by PIs Grotewiel (fly) and Miles (mouse) and is designed to have several major points of integration. Clic4/Clic was originally implicated as a candidate gene for ethanol behavior by a series of analyses by the Miles laboratory on gene expression, linkage and association data. Subsequent genetic analysis of Clic in the fly by the Grotewiel laboratory made Clic4 a high priority locus for ethanol behavioral studies in the mouse (described as preliminary data). These studies come together to rationally support a more extensive investigation of how Clic/Clic4 influences ethanol responses in flies (Aims 1 and 2) and mice (Aims 4A and 4B). Furthermore, additional studies on ethanol-responsive genes in the mouse (Aims 4A and 4C) are now informing the design of experiments in flies that will investigate mechanisms of Clic action (Aim 3). The results of the Drosophila studies in Aim 3 will in turn guide the design of experiments in mice on mechanisms for Clic4 in mammalian ethanol behavior (Aim 4D). The deliberate cross-species integration in this project, implemented within a collaborative framework between the Miles and Grotewiel laboratories, will drive a vigorous genetic investigation of conserved mechanisms underlying ethanol behavior.